[6.12.10] - Stop array script doesn't check to see if a disk is already unmounted.

I was in the process of removing a data drive from the array (shrinking it)

and:

1. The docs need to be updated: here

    It references user scripts that don't work post 6.12

2. Those instructions for manually zeroing the drive break the stop array procedure

    The docs call for unmounting the drive then zero-ing it out.  That all worked fine. The problem

    came when trying to stop the array.  The stop array script seems to want confirmation of a unmounting.

    since the disk was already unmounted it was looping forever trying to unmount a disk that was already unmounted.

    the script should probably check to see if a disk is already unmounted.  I know this is not a frequent occurrence..  but it can happen in this case.

Here is the output from the log:

Sep 21 10:51:21 Tower emhttpd: shcmd (3175801): umount /mnt/disk9
Sep 21 10:51:21 Tower root: umount: /mnt/disk9: not mounted.
Sep 21 10:51:21 Tower emhttpd: shcmd (3175801): exit status: 32
Sep 21 10:51:21 Tower emhttpd: Retry unmounting disk share(s)...
Sep 21 10:51:26 Tower emhttpd: Unmounting disks...